Preoperative Medical Evaluation

1
Preoperative Medical Evaluation

• Colin McMahon, MD.
• Division of Combined Internal Medicine and
  Pediatrics
• University at Buffalo, School of Medicine

2
What are You Really Being Asked to Do?

• Assess risks of anesthesia
• Assess the risks of the procedure
• Manage complicated medical problems
• Predict the future

3
General Considerations

• Limit number of recommendations
• Focus on critical problems
• Be specific about drugs, dosage and intervals
• Dont ask the surgeon to think

4
General Approach

• Diagnosis
• Develop a problem list
• Treatment
• Directed toward decreasing surgical risk
• Prognosis
• Anesthesia complications
• Procedural complications

5
Misconceptions

• Advise on type of anesthesia
• General, local or spinal
• Change ongoing treatment plans
• Initiate diagnostic work-ups

6
Risk Evaluation

• Overall perioperative mortality 0.3
• Anesthesia induction 10
• Intraoperatively 35
• Postoperatively (48 hours) 55

7
ASA Classification
8
Procedure Risk

• Low risk
• Eye surgery, oral surgery, DC, hysterectomy,
  herniorrhaphy
• High risk
• Craniotomy and cardiovascular

9
Specific Risks

• Pulmonary
• Cardiac
• Hematologic
• Endocrine
• Thromboembolism Prophylaxis

10
Pulmonary Risks

• Complications
• Hypoventilation
• Pneumonia
• Atelectasis
• Occur in about a third of patients
• Accounts for half of perioperative mortality

11
Whos at Risk

• Smokers
• COPD
• Obesity
• Age gt 70
• Thoracic surgery
• Upper abdominal surgery
• Anesthesia gt 2 hours

12
Risk Assessment

• FEV1 gt 2L, probably safe
• FEV1 between 1 and 2L, increased risk
• FEV1 lt1L, high risk

13
Risk Management

• Quit smoking
• Bronchodilator therapy
• CPT
• Early treatment of bronchitis
• Early mobilization

14
Cardiac Risks

• Complications
• Myocardial Infarction
• CHF
• Hypertension
• 50 fatal, 60 silent
• Increased mortality post-op day 3

15
Whos at Risk

• Recent MI
• Valvular heart disease
• CHF
• Unstable angina
• Diabetes

16
Risk Assessment

• Goldman Cardiac Risk-Index for Noncardiac Surgery
• American College of Cardiology Risk Assessment

17
Risk Management

• Monitor for perioperative ischemia
• Repair severe aortic stenosis first
• Treat CHF aggresively preoperative
• Postpone non-emergent procedures for at least 6
  months after an MI

18
Hemetologic Risks

• Complications
• Thromboembolic
• Bleeding

19
Whos at Risk

• Polycythemia vera
• Thrombocytopenia

20
Risk Assessment

• Hematocrit
• Platelet count
• Bleeding time
• PT/PTT

21
Risk Management

• Phlebotomy to decrease hct lt 45
• Maintain plts gt 50,000

22
Endocrine Risks

• Thyroid storm
• Diabetic complications

23
Risk Management

• Good control of thyroid function for at least 3
  months prior
• Hold oral hypoglycemics
• Reduce insulin by half

24
Thrombembolic Prophylaxis

• Specific to surgery
• Increased risk
• Elderly
• Obesity
• Prolonged anesthesia
• Immobility

25
Other Considerations

• Antibiotic prophylaxis
• Herbal medicines
• Geriatric patient